1. Field of the Invention
The invention relates to antimicrobial compounds and in particular to antimicrobial compounds for use in polymeric compositions.
2. Prior Art Statement
The applicant considers the following U.S. Patents to be the most pertinent prior art known to him.
______________________________________ 2,686,786 Shaw & Bernstein 2,809,971 Bernstein & Losee 3,027,372 Starrs 3,533,993 Hovey 4,363,663 Hill ______________________________________
The Shaw and Bernstein patent discloses both the preparation of 2-mercaptopyridine-1-oxide and its antibacterial activity.
Bernstein and Losee describe the preparation of a number of heavy metal salt derivatives of 2-mercaptopyridine-1-oxide.
Starrs discloses a tin salt derivative of 2-mercaptopyridine-1-oxide and its method of preparation. He also discloses its use as a fungicide on a number of materials.
Hovey discloses the use of 2-mercaptopyridine-1-oxide as a stabilizer of vinyl chloride resins against heat degradation.
Hill (previous patent of present inventor) discloses the use of organophosphorus compounds in preparation of antimicrobial solutions. The patent discloses that solutions containing the organophosphorus compounds produce less degradation in appearance of plastic resins in which they are utilized than the same antimicrobial agent without the organophosphorus compound.
Since 1970, when the Hovey patent was issued, fusion times have been shortened and process temperatures increased. These modern conditions of time and temperature preclude the use of 2-mercaptopyridine-1-oxide and its derivatives as thermal stabilizers or as antimicrobial compounds in plastics because they discolor any polymer system containing them. Even small amounts of ultraviolet light increase the discoloration caused by 2-mercaptopyridine-1-oxide or its derivatives in a polymer system. Heat and light stabilizers are commonly used in polymer systems, but no addition of these or ultraviolet absorbers effectively stabilizers 2-mercaptopyridine-1-oxide or a derivative against the effects of process heat or ultraviolet light.